1. Field of the Invention
The invention is related to the field of communication networks and, in particular, to IMS networks that store information on the access network of a user in a subscriber profile for the user.
2. Statement of the Problem
One type of communication network gaining popularity is an IP Multimedia Subsystem (IMS) network. As set forth in the 3rd Generation Partnership Project (3GPP), IMS provides a common core network having a network architecture that allows for various types of access networks. The access network between a communication device and the IMS network may be a cellular network (e.g., CDMA or GSM), a WLAN (e.g., WiFi or WiMAX), an Ethernet network, or another type of wireless or wireline access network. The IMS architecture is initially defined by the 3GPP to provide multimedia services to communication devices over an Internet Protocol (IP) network, as IP networks have become the most cost savings bearer network to transmit video, voice, and data. Service providers are accepting this architecture in next generation network evolution.
Before a communication device receives service from an IMS network, the communication device attempts to register with the IMS network. To register according to 3GPP standards, the communication device transmits a register request message, such as a SIP REGISTER message, to a Proxy-Call Session Control Function (P-CSCF) through the appropriate access network. The P-CSCF identifies the home network for the communication device, and then transmits another register request message to a Serving-Call Session Control Function (S-CSCF) in the home network of the user. Responsive to the register request message, the S-CSCF generates an authentication request message, such as a Diameter Multimedia Authentication Request (MAR) message, and transmits the authentication request message to a Home Subscriber Server (HSS). The HSS then authenticates the communication device using the AKA authentication method or another type of authentication method. If the communication device is authenticated, then the S-CSCF generates a subscriber profile request message, such as a Diameter Server Assignment Request (SAR) message, and transmits the subscriber profile request message to the HSS. Responsive to the subscriber profile request message, the HSS identifies the subscriber profile for the user of the communication device. The HSS then transmits a response message, such as a Diameter Server Assignment Answer (SAA) message, to the S-CSCF that includes the subscriber profile for the user of the communication device. The S-CSCF may then process the subscriber profile to provide services for the communication device.
Some communication devices are able to identify information on the access network through which they are communicating, and include the access network information in the register request message to the P-CSCF. For example, a WiFi access point may broadcast its MAC address to all communication devices within its service area. A communication device in range of the WiFi access point may identify the MAC address of the WiFi access point and embed the MAC address in the register request message to the P-CSCF.
One problem with present IMS networks is that if the P-CSCF receives access network information from a communication device, the P-CSCF does not forward the access network information to other nodes in the IMS network, such as the S-CSCF and the HSS. According to the 3GPP standards, the registration process by the S-CSCF and the HSS involves authenticating the user. As such, there is no suggestion to forward the access network information to the S-CSCF and the HSS during registration, as this information is not presently used to authenticate the user. As a result, the access network information is not presently provided to other nodes in the IMS network, such as the S-CSCF and the HSS, and is not presently stored in the subscriber profile of a user. The access network information may be useful for providing other features or services in the IMS network, but is unfortunately not utilized in present IMS networks.